Supercurrent and phase slips in a ballistic carbon nanotube embedded into a van der Waals heterostructure

TL;DR

This paper reports the observation of long-range superconducting correlations and phase slips in a ballistic carbon nanotube embedded in a van der Waals heterostructure, with implications for Majorana fermion research.

Contribution

It demonstrates long-range superconductivity and phase slip phenomena in a carbon nanotube within a novel heterostructure, advancing potential quantum computing applications.

Findings

Supercurrent flows through the nanotube section beneath NbSe2 and beyond.

Resistance steps indicate phase slip centers during superconductivity breakdown.

Hybrid device components are suitable for Majorana fermion realization.

Abstract

We demonstrate long-range superconducting correlations in a several micrometer-long carbon nanotube encapsulated in a van der Waals stack between hBN and NbSe$_2$. We show that a substantial supercurrent flows through the nanotube section beneath the NbSe$_2$ crystal as well as through the 2 $\mu$m-long section not in contact with it. As expected for superconductors of nanoscopic cross section, the current-induced breakdown of superconductivity is characterized by resistance steps due to the nucleation of phase slip centers. All elements of our hybrid device are active building blocks of several recently proposed setups for realization of Majorana fermions in carbon nanotubes.